One of the major performance tests imposed on a class of electromagnetic devices known as machine tool relays is that the relays must satisfy the parameters of a Life or Load Test as well as a Contact Fidelity Test. To satisfy the requirements of the Life or Load Test, five relays when tested must have a minimum average life of 13 million operations and a minimum life of 10 million operations without any failures of a mechanical or electrical nature. To satisfy the Contact Fidelity Test, five relays are wired in a modified timed open loop rat race circuit with the five relays furnishing 36 contacts in the circuit. To satisfy the test, the relays must achieve seven million trouble free operations without adjustment or repair and the 36 contacts must function properly for a minimum agregate of 50 million contact operations per failure with the test terminated and the final results calculated after five contacts have failed.